Eyeing Industrial Excess for Home Heating in the U.K.

The steel factories of Sheffield, England, pay a lot of money to cool down the water and gases they get rid of at the end of their manufacturing processes. At the same time, the people of Sheffield pay a lot of money to heat their homes up in a part of England that has average winter temperatures in the mid 30s. Researchers are now eying a two-birds, one-stone solution: redirecting some of that wasted heat from the factories into the town's heating system, which would reduce costs on both sides and help bring down the city's overall carbon emissions.

It's a method that could be used and expanded to provide for about 20 percent of the U.K.'s entire heating needs, according to researchers at the University of Sheffield's Faculty of Engineering. In an article recently published in the journal Energy Conversion and Management, the researchers show that simply redirecting the heat form these factories could provide heating for about 2,000 homes in the city.

Sheffield built a district heating system in the 1970s, which captures and recirculates the heat generated from burning the city's non-recyclable garbage. This produces about 21 megawatts of electricity per year, enough to power 22,000 homes. The system also produces about 60 megawatts of thermal energy through steam, which provides heating and hot water to more than 3,000 homes. It's the largest district heating system in the U.K.

Researchers estimate that the excess heat from factories could add an additional 20 megawatts of thermal energy to the system. Reusing this waste heat could also reduce the city's annual carbon dioxide emissions by about 80,000 tons – about 3 percent of the city's total emissions.

This technique works in Sheffield mainly thanks to the close proximity of steel factories to residential areas. The researchers identified six parts of town where the factories are close enough to easily tap into the city's existing district heating system. And given the amount of similar factories and heat-producers in other cities throughout the U.K., the researchers estimate that excess factory heat could be redirected to other district-systems to heat more than 5.5 million homes.